Pub Date : 2024-07-01DOI: 10.62913/engj.v61i3.1329
Bo Dowswell
Shear yielding is the controlling limit state for most round HSS members subjected to torsion; however, buckling is a limit state that can reduce the torsional strength of members with high diameter-to-wall thickness (D/t) ratios. The purposes of this paper are to summarize the available research on the torsional performance of round HSS members and evaluate the applicable provisions in the AISC Specification. A historical review of the available research revealed 125 experimental tests from seven projects, leading to evolving design methods over the last century. An evaluation of the AISC Specification provisions indicated an appropriate reliability level for the yielding limit state; however, the target reliability for buckling is met only for long specimens. A new equation is proposed to predict the buckling strength of intermediate-length members.
{"title":"Torsional Design of Round HSS Members— A Critical Review","authors":"Bo Dowswell","doi":"10.62913/engj.v61i3.1329","DOIUrl":"https://doi.org/10.62913/engj.v61i3.1329","url":null,"abstract":"Shear yielding is the controlling limit state for most round HSS members subjected to torsion; however, buckling is a limit state that can reduce the torsional strength of members with high diameter-to-wall thickness (D/t) ratios. The purposes of this paper are to summarize the available research on the torsional performance of round HSS members and evaluate the applicable provisions in the AISC Specification. A historical review of the available research revealed 125 experimental tests from seven projects, leading to evolving design methods over the last century. An evaluation of the AISC Specification provisions indicated an appropriate reliability level for the yielding limit state; however, the target reliability for buckling is met only for long specimens. A new equation is proposed to predict the buckling strength of intermediate-length members.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141702257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.62913/engj.v61i3.1326
Kara Stall, Andrea Culhane, Likun Sun, Rachel Chicchi Cross, Matthew Steiner
High strength structural steels (with yield stresses greater than 65 ksi) may have notably different material characteristics when compared to structural steels conventionally used in building construction [i.e., ASTM A992/A992M (2022) or A572/A572M Gr. 50 (2021)]. This paper presents findings from an experimental program that investigated the material characterization of ASTM A656/A656M Gr. 80 (2024) plate steel. The results obtained were compared to conventional ASTM A572/A572M Gr. 50 steel. Two types of testing were performed for this work: tensile coupon testing and residual stress testing. The tensile coupon testing was carried out for both the A656/A656M Gr. 80 and A572/A572M Gr. 50 plate material. The A656/A656M Gr. 80 plate material showed more variation between the two different plate thicknesses in both mechanical behavior and microstructure due to differences in steel production. The 0.375 in. thick plate exhibited a clear yield plateau with an ultimate/yield stress ratio similar to the Gr. 50 material. In contrast, the 0.5 in. plate did not have a yield plateau and reached lower ultimate strain. The residual stress testing was performed using a sectioning technique for one A572/A572M Gr. 50 and five A656/A656M Gr. 80 built-up sections that were fabricated from 0.5 in. and 0.375 in. plate material. Residual stresses obtained from measurements were compared to previously published predictive models. The ECCS model and BSK99 models were found to be reasonable predictors of residual stresses for all specimens except the one section fabricated from 0.5 in. thick Gr. 80 plate. When comparing the Gr. 50 and Gr. 80 specimens of the same cross-sectional geometry, the residual stresses were similar, implying that cross-sectional geometry is more prevalent than the nominal yield stress in determining residual stresses in built-up I-sections.
高强度结构钢（屈服应力大于 65 ksi）与建筑施工中常用的结构钢[即 ASTM A992/A992M (2022) 或 A572/A572M Gr. 50 (2021)]相比，可能具有明显不同的材料特性。本文介绍了一项实验计划的结果，该计划研究了 ASTM A656/A656M Gr. 80 (2024) 板钢的材料特性。获得的结果与传统的 ASTM A572/A572M Gr. 50 钢进行了比较。这项工作进行了两种类型的测试：拉伸试样测试和残余应力测试。对 A656/A656M Gr. 80 和 A572/A572M Gr. 50 钢板材料都进行了拉伸试样测试。由于钢材生产的不同，A656/A656M Gr. 80 钢板材料在机械性能和微观结构方面的差异较大。0.375 英寸厚的钢板表现出明显的屈服平台，极限/屈服应力比与 Gr.相比之下，0.5 英寸厚的钢板没有屈服高原，极限应变也较低。残余应力测试采用切片技术，对由 0.5 英寸和 0.375 英寸钢板材料制成的一个 A572/A572M Gr. 50 和五个 A656/A656M Gr. 80 构建截面进行了测试。通过测量获得的残余应力与之前公布的预测模型进行了比较。结果发现，ECCS 模型和 BSK99 模型是所有试样残余应力的合理预测模型，只有一个试样是用 0.5 英寸厚的 Gr. 80 板材制造的。在比较横截面几何形状相同的 Gr. 50 和 Gr. 80 试样时，残余应力相似，这意味着横截面几何形状比标称屈服应力更能决定加固 I 型截面中的残余应力。
{"title":"Tensile Coupon Testing and Residual Stress Measurements of High-Strength Steel Built-Up I-Shaped Sections","authors":"Kara Stall, Andrea Culhane, Likun Sun, Rachel Chicchi Cross, Matthew Steiner","doi":"10.62913/engj.v61i3.1326","DOIUrl":"https://doi.org/10.62913/engj.v61i3.1326","url":null,"abstract":"High strength structural steels (with yield stresses greater than 65 ksi) may have notably different material characteristics when compared to structural steels conventionally used in building construction [i.e., ASTM A992/A992M (2022) or A572/A572M Gr. 50 (2021)]. This paper presents findings from an experimental program that investigated the material characterization of ASTM A656/A656M Gr. 80 (2024) plate steel. The results obtained were compared to conventional ASTM A572/A572M Gr. 50 steel. Two types of testing were performed for this work: tensile coupon testing and residual stress testing. The tensile coupon testing was carried out for both the A656/A656M Gr. 80 and A572/A572M Gr. 50 plate material. The A656/A656M Gr. 80 plate material showed more variation between the two different plate thicknesses in both mechanical behavior and microstructure due to differences in steel production. The 0.375 in. thick plate exhibited a clear yield plateau with an ultimate/yield stress ratio similar to the Gr. 50 material. In contrast, the 0.5 in. plate did not have a yield plateau and reached lower ultimate strain. The residual stress testing was performed using a sectioning technique for one A572/A572M Gr. 50 and five A656/A656M Gr. 80 built-up sections that were fabricated from 0.5 in. and 0.375 in. plate material. Residual stresses obtained from measurements were compared to previously published predictive models. The ECCS model and BSK99 models were found to be reasonable predictors of residual stresses for all specimens except the one section fabricated from 0.5 in. thick Gr. 80 plate. When comparing the Gr. 50 and Gr. 80 specimens of the same cross-sectional geometry, the residual stresses were similar, implying that cross-sectional geometry is more prevalent than the nominal yield stress in determining residual stresses in built-up I-sections.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141689183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.62913/engj.v61i3.1328
Namita Nayak, P.M. Anilkumar, L. Subramanian
Lateral torsional buckling (LTB) is of concern in long-span flexural members, particularly in the negative flexure regions of continuous-span, steel I-shaped members and during construction. While the elastic critical LTB capacity of a simply supported I-shaped member subjected to uniform moment has a closed-form solution, most LTB modification factors for beams subjected to moment gradients in the literature are empirical and work well only for specific loading and boundary conditions. This paper investigates the suitability of the different LTB modification factors in literature and design specifications for various loading and boundary conditions, accomplished via comparisons with analytical solutions using the Rayleigh-Ritz method and numerical solutions from finite element analyses. The analytical LTB modification factors are derived for doubly symmetric I-shaped members with different combinations of ideal flexural and torsional boundary conditions (simply supported and fixed) and subjected to different loading scenarios. The validity of the LTB modification factors determined using the Rayleigh-Ritz method and other formulae in the literature are also assessed for realistic intermediate restraint conditions, which are neither fully pinned nor fixed, by examining laterally continuous beams. Demonstrating that current design specifications for elastic critical LTB modifications are overly conservative
{"title":"Lateral-Torsional Buckling Modification Factors in Steel I-Shaped Members: Recommendations Using Energy-Based Formulations","authors":"Namita Nayak, P.M. Anilkumar, L. Subramanian","doi":"10.62913/engj.v61i3.1328","DOIUrl":"https://doi.org/10.62913/engj.v61i3.1328","url":null,"abstract":"Lateral torsional buckling (LTB) is of concern in long-span flexural members, particularly in the negative flexure regions of continuous-span, steel I-shaped members and during construction. While the elastic critical LTB capacity of a simply supported I-shaped member subjected to uniform moment has a closed-form solution, most LTB modification factors for beams subjected to moment gradients in the literature are empirical and work well only for specific loading and boundary conditions. This paper investigates the suitability of the different LTB modification factors in literature and design specifications for various loading and boundary conditions, accomplished via comparisons with analytical solutions using the Rayleigh-Ritz method and numerical solutions from finite element analyses. The analytical LTB modification factors are derived for doubly symmetric I-shaped members with different combinations of ideal flexural and torsional boundary conditions (simply supported and fixed) and subjected to different loading scenarios. The validity of the LTB modification factors determined using the Rayleigh-Ritz method and other formulae in the literature are also assessed for realistic intermediate restraint conditions, which are neither fully pinned nor fixed, by examining laterally continuous beams. Demonstrating that current design specifications for elastic critical LTB modifications are overly conservative","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141696688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.62913/engj.v61i2.1325
Judy Liu
Ongoing research on innovative steel bridge decks is highlighted. This study, currently under way at the University of Kansas, is led by Dr. William Collins, Associate Professor in the Department of Civil, Environmental, and Architectural Engineering. Dr. Collins’s research interests include fatigue and fracture of metallic structures; bridge design, fabrication, construction, and performance; and evaluation and preservation of historic structures. Among Dr. Collins’s accolades are the Robert J. Dexter Memorial Award, a Fulbright Scholar Award to conduct fracture mechanics research in Finland, and the AISC Milek Fellowship. The four-year Milek Fellowship is supporting this research on innovative steel deck systems for highway bridge applications—the first Milek Fellowship project to focus on bridges. Selected highlights from the work to date are presented, along with a preview of future research tasks.
重点介绍正在进行的创新钢桥面研究。这项研究目前正在堪萨斯大学进行，由土木、环境和建筑工程系副教授 William Collins 博士领导。柯林斯博士的研究兴趣包括金属结构的疲劳和断裂；桥梁设计、制造、施工和性能；以及历史结构的评估和保护。柯林斯博士曾获得罗伯特-J-德克斯特纪念奖（Robert J. Dexter Memorial Award）、赴芬兰进行断裂力学研究的富布赖特学者奖（Fulbright Scholar Award）和美国国际工程学会米莱克奖学金（AISC Milek Fellowship）。为期四年的 Milek 奖学金用于支持这项有关公路桥梁应用的创新钢桥面系统的研究--这是 Milek 奖学金首个侧重于桥梁的项目。本文介绍了迄今为止的部分重点工作，以及未来的研究任务。
{"title":"Steel Structures Research Update: Innovative Steel Deck System for Highway Bridge Applications","authors":"Judy Liu","doi":"10.62913/engj.v61i2.1325","DOIUrl":"https://doi.org/10.62913/engj.v61i2.1325","url":null,"abstract":"Ongoing research on innovative steel bridge decks is highlighted. This study, currently under way at the University of Kansas, is led by Dr. William Collins, Associate Professor in the Department of Civil, Environmental, and Architectural Engineering. Dr. Collins’s research interests include fatigue and fracture of metallic structures; bridge design, fabrication, construction, and performance; and evaluation and preservation of historic structures. Among Dr. Collins’s accolades are the Robert J. Dexter Memorial Award, a Fulbright Scholar Award to conduct fracture mechanics research in Finland, and the AISC Milek Fellowship. The four-year Milek Fellowship is supporting this research on innovative steel deck systems for highway bridge applications—the first Milek Fellowship project to focus on bridges. Selected highlights from the work to date are presented, along with a preview of future research tasks.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140768760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.62913/engj.v61i2.1322
Ralph M. Richard, Eric Keldrauk, Jay Allen
Braced frames intended to resist wind and seismic loads traditionally have been analyzed and designed as trusses with all joints modeled as pins, such that only the braces provide lateral force resistance. However, frames with gusset plate connections create a rigid joint zone between frame beams and columns, effectively resulting in moment frame behavior, particularly at larger drift angles when braces have yielded or buckled. Described herein are the force distributions for buckling-restrained braced frames (BRBF) subjected to story drift angles, where the lateral resistance of the frame comprises both brace and moment frame action.
{"title":"Lateral Force Distributions in Braced-Moment Frames","authors":"Ralph M. Richard, Eric Keldrauk, Jay Allen","doi":"10.62913/engj.v61i2.1322","DOIUrl":"https://doi.org/10.62913/engj.v61i2.1322","url":null,"abstract":"Braced frames intended to resist wind and seismic loads traditionally have been analyzed and designed as trusses with all joints modeled as pins, such that only the braces provide lateral force resistance. However, frames with gusset plate connections create a rigid joint zone between frame beams and columns, effectively resulting in moment frame behavior, particularly at larger drift angles when braces have yielded or buckled. Described herein are the force distributions for buckling-restrained braced frames (BRBF) subjected to story drift angles, where the lateral resistance of the frame comprises both brace and moment frame action.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140786868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.62913/engj.v61i2.1324
Paul A. Cozzens, Gian Adrea Rassati, James A. Swanson, Thomas M. Burns
Since the 13th edition, the AISC Steel Construction Manual has included provisions regarding the recommended minimum plate washer thickness used in a column base plate and anchor rod assembly. Each plate washer must have sufficient strength and stiffness to fully develop the anchor rod to which it is fastened without succumbing to pull-through, flexural, or cracking failure. Laboratory tensile testing of an anchor rod, nut, and plate washer assembly was conducted at the University of Cincinnati to study plate washer performance. This testing investigated the capacity of ASTM A572/A572M Grade 50 plate washers using the recommended minimum thicknesses as listed in Table 14-2 of the 15th edition of the AISC Steel Construction Manual, with anchor rods having ¾, 1, 1½, 2, and 2½ in. diameter. A total of 94 tests were conducted, after which the plate washers were visually assessed for signs of failure, including measurement of permanent out-of-plane deformation. This assessment established that a 40% relative deformation in plate washers could reasonably be judged as a failure threshold due to excessive deformation. Testing and assessment revealed that while 10 plate washers exhibited relative deformations in excess of 40%, the recommended minimum plate washer thicknesses found in AISC Manual Table 14-2 were sufficient in fully developing most anchor rods. The notable exception to the current minimum thickness recommendations were for washers in use with anchor rods with diameters of ¾, 1, and 1½ in. made from Grade 105 steel. For these anchor rods, a thicker plate washer than that currently specified is recommended. Testing also found that the anchor rod orientation and the variations of ultimate strength in individual anchor rods did not appear to be significantly associated with the performance of plate washers in these tests.
{"title":"Investigation of Steel Plate Washer Thickness for Column Anchor Rod Applications","authors":"Paul A. Cozzens, Gian Adrea Rassati, James A. Swanson, Thomas M. Burns","doi":"10.62913/engj.v61i2.1324","DOIUrl":"https://doi.org/10.62913/engj.v61i2.1324","url":null,"abstract":"Since the 13th edition, the AISC Steel Construction Manual has included provisions regarding the recommended minimum plate washer thickness used in a column base plate and anchor rod assembly. Each plate washer must have sufficient strength and stiffness to fully develop the anchor rod to which it is fastened without succumbing to pull-through, flexural, or cracking failure. Laboratory tensile testing of an anchor rod, nut, and plate washer assembly was conducted at the University of Cincinnati to study plate washer performance. This testing investigated the capacity of ASTM A572/A572M Grade 50 plate washers using the recommended minimum thicknesses as listed in Table 14-2 of the 15th edition of the AISC Steel Construction Manual, with anchor rods having ¾, 1, 1½, 2, and 2½ in. diameter. A total of 94 tests were conducted, after which the plate washers were visually assessed for signs of failure, including measurement of permanent out-of-plane deformation. This assessment established that a 40% relative deformation in plate washers could reasonably be judged as a failure threshold due to excessive deformation. Testing and assessment revealed that while 10 plate washers exhibited relative deformations in excess of 40%, the recommended minimum plate washer thicknesses found in AISC Manual Table 14-2 were sufficient in fully developing most anchor rods. The notable exception to the current minimum thickness recommendations were for washers in use with anchor rods with diameters of ¾, 1, and 1½ in. made from Grade 105 steel. For these anchor rods, a thicker plate washer than that currently specified is recommended. Testing also found that the anchor rod orientation and the variations of ultimate strength in individual anchor rods did not appear to be significantly associated with the performance of plate washers in these tests.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140784418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.62913/engj.v61i2.1323
Albert Ku, Farrel Zwerneman, Steve Gunzelman, Jieyan Chen
The offshore design standards for U.S. practices refer to AISC specifications when designing structural components with nontubular shapes. The widely used API RP-2A WSD standard (API, 2014) asks designers to use the 1989 AISC Specification. The newly published API RP-2A LRFD and RP-2TOP ask designers to use the 2010 AISC Specification. Although the 2010 AISC Specification has been partially adopted by API, the current offshore practice is still primarily dominated by the 1989 AISC Specification. The key issue hampering the offshore community’s full adoption of the 2010 AISC Specification is the relative ease of accounting for second-order effects in the 1989 AISC Specification. In 2019, API formed a Task Group dedicated to studying this issue, with the main findings summarized in this paper. By illustrating the key code check process in two examples with an easy-to-understand format, this paper aims to assist offshore structural engineers to better understand the latest AISC specification. The authors also hope that this paper will serve as a communication path between the offshore structural community and AISC for current and future standards’ adoption and harmonization.
{"title":"The Adoption of AISC 360 for Offshore Structural Design Practices","authors":"Albert Ku, Farrel Zwerneman, Steve Gunzelman, Jieyan Chen","doi":"10.62913/engj.v61i2.1323","DOIUrl":"https://doi.org/10.62913/engj.v61i2.1323","url":null,"abstract":"The offshore design standards for U.S. practices refer to AISC specifications when designing structural components with nontubular shapes. The widely used API RP-2A WSD standard (API, 2014) asks designers to use the 1989 AISC Specification. The newly published API RP-2A LRFD and RP-2TOP ask designers to use the 2010 AISC Specification. Although the 2010 AISC Specification has been partially adopted by API, the current offshore practice is still primarily dominated by the 1989 AISC Specification. The key issue hampering the offshore community’s full adoption of the 2010 AISC Specification is the relative ease of accounting for second-order effects in the 1989 AISC Specification. In 2019, API formed a Task Group dedicated to studying this issue, with the main findings summarized in this paper. By illustrating the key code check process in two examples with an easy-to-understand format, this paper aims to assist offshore structural engineers to better understand the latest AISC specification. The authors also hope that this paper will serve as a communication path between the offshore structural community and AISC for current and future standards’ adoption and harmonization.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140764272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-31DOI: 10.4186/ej.2023.27.12.23
A. Agathiyan, A. Gowrisankar, Pankajam Natarajan, Kishore Bingi, N. Shaik
{"title":"Note on Fourier Transform of Hidden Variable Fractal Interpolation","authors":"A. Agathiyan, A. Gowrisankar, Pankajam Natarajan, Kishore Bingi, N. Shaik","doi":"10.4186/ej.2023.27.12.23","DOIUrl":"https://doi.org/10.4186/ej.2023.27.12.23","url":null,"abstract":"","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139134801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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